Method and apparatus for packaging

ABSTRACT

The invention relates to a method of forming packages for articles by feeding layers of wrapping film along aligned paths in the same direction, causing these layers of wrapping film to adhere to each other at transversely extending positions spaced apart relatively to the direction of feed, and then opening out the two layers between two successive adhering regions so that the length of film between the adhering regions forms a tube. The invention also includes a method and means whereby an opening device is introduced between the two layers of film whilst the film is in a flattened condition, and then the opennig deivce is activated to open out the tube to allow an article to be inserted therein.

United States Patent 1191 1111 3,881,296

Bate May 6, 1975 METHOD AND APPARATUS FOR 3,393,493 7/1968 Membrino 53/29 x PACKAGING 3,509,681 5/1970 Sass 53/252 X 3,653,177 4/1972 Adams et a1 53/182 Inventor: Frederick Douglas Clavell Bate, 155

Barkerhouse Rd., Nelson, England Filed: Mar. 15, 1973 Appl. No.: 341,526

Foreign Application Priority Data June 29, 1972 United Kingdom 30399/72 US. Cl. 53/30; 53/29; 53/182; 53/183', 53/184; 53/252; 53/384 Int. Cl B65b 9/02; B65b 9/14; B65b 43/08 Field of Search 53/28, 29, 30 S, 180, 182, 53/183, 184, 187, 252, 384

References Cited UNITED STATES PATENTS Primary ExaminerRobert L. Spruill Attorney, Agent, or Firm-Norris &, Bateman [57] ABSTRACT The invention relates to a method of forming packages for articles by feeding layers of wrapping film along aligned paths in the same direction, causing these layers of wrapping film to adhere to each other at transversely extending positions spaced apart relatively to the direction of feed, and then opening out the two layers between two successive adhering regions so that the length of film between the adhering regions forms a tube. The invention also includes a method and means whereby an opening device is introduced between the two layers of film whilst the film is in a flattened condition, and then the opennig deivce is acti vated to open out the tube to allow an article to be inserted therein.

33 Claims, 30 Drawing Figures PATENTEEHAY 6l975 1 295 SHEET UlUF 16 PKJENTEE rm 6 i9T5 SHEET FIG. 6.

PATENIEBMAY 6191's 3,881,296

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ATENTEE MAY 6% SHEET l20F 16 WJERTEIY MAY 615175 SHEET l 0F 16 vmv wm OE Prmzrmw 61875 3,881,296

SHEET lSOF 16 RATENIESMAY 6|975 3,881,296 sum lBOF 1s METHOD AND APPARATUS FOR PACKAGING This invention relates broadly to the packaging of goods, and the invention is particularly useful in relation to shrink wrapping. In its broadest aspect however, the invention is concerned with the formation of a fiexible tube or open-ended bag of wrapping material into which an article or articles to be wrapped can be placed. The shrink wrapping process requires the article(s) to be placed in a bag of heat-shrinkable plastics film and the invention can therefore be used to provide such a bag, but it is to be understood that the invention could also be used to provide packaging bags which do not require shrinking.

In a known method of wrapping articles in a tube of plastics film prior to a shrinking operation, two sources of film are used, and the free ends of the two films are sealed together so that there is formed a barrier of film extending vertically between the two supply sources (usually reels). An article to be wrapped-and the expression article will be used herein to include a collection of articles which are to be wrapped together as a collation is then traversed in a direction at right angles to and passing through the film barrier. As a result film is drawn off the supply sources and the film becomes wrapped first over the leading side of the article, and then over the top and bottom of the article. The two films are then brought together on the trailing side of the article and severed on a transverse line and simultaneously sealed together on both sides of the line of cut. The article is then wrapped in a tube of film which is open at both ends, and a fresh barrier of film is created ready to receive the next article. The film is considerably wider than the article, and hence the tube overhangs the article at both ends. These overhanging parts of the tube can be gathered and sealed together so that the article is totally enclosed ready for the heat shrinking of the film wrapping, or the overlapping parts of the film can simply be allowed to contract on to the ends of the article if total enclosure by the wrapping film is not essential.

Practical experience shows this method of wrapping an article has disadvantages when wrapping some articles particularly when the film is used as an outer wrap on articles already packed in some kind of container. The problem arises because of the bulky shape of the wrap, and it is an object of the invention to provide a method of forming a package for an article, and apparatus for carrying out the method, which produces better packaging than the known method referred to above. It is a further object of the invention to provide a method of packaging and apparatus therefor which is capable of operating at higher speeds than those of known apparatus.

GENERAL FEATURES OF THE INVENTION According to this invention a method of forming a package for an article comprises feeding two layers of wrapping film in proximity to each other along aligned paths in the same direction, causing an adherant relationship between the two layers of film at transversely extending positions spaced apart relatively to the direction of feed, and then opening out the two layers between two successive adhering regions so that the length of film between the adhering regions forms a tube.

Preferably the two layers of film are made of thermoplastic material, and the adherance is produced by heat sealing. Known materials which are used for wrapping purposes, particularly those used in the wrapping of goods, such as polyvinylchloride are suitable as these are thermoplastic and suitable for heat sealing, and heat severing. It is also preferred to sever the film on a transverse line of cut at each adherant region so that the tube is detached from the preceding tube and from the film being fed to the tube-forming position. The cut may be made by the application of heat.

The film may be supplied in the form of two completely separate flat sheets drawn off separate reels or it may be supplied from a single source in the form of centre-folded double layer film, or any other commercially available double layer film such as J-folded film.

Preferably the two layers are superimposed one on the other as they are being fed and sealed, so that after the seals are formed, the two layers of film are each stretched lengthwise between the seals and they form a substantially flat envelope which subsequently opens out into the tube. It is much easier to produce adequate seals at speed, when the two layers of film are lying flat one against the other than if they are stretched around a relatively bulky article as in the known method previously described, and this presents one of the advantages of the invention.

For opening the tube a tube opening device may be inserted between the two film layers before the layers are caused to adhere to each other, and after the layers have been caused to adhere the device may be activated to open the tube. In a preferred method the tube opening device is a mechanism which is introduced between the film in a collapsed condition in which condition the mechanism is of a minimum thickness, and the method includes the step of operating this mechanism into an erect condition in which it opens out the tube. Alternatively, the tube opening device may be in the form of a nozzle which is inserted between the two layers, and gas is blown out through this nozzle to open the tube.

According to another preferred feature of the invention, an article to be wrapped is fed into the opened out tube by introducing the article from one end. This may be achieved by causing the tube to move laterally over the article whilst the tube and the article are travelling along side-by-side paths. The article may also be moved laterally but in the opposite direction to the tube.

Indeed in a possible method of carrying out the invention alternate articles are introduced into their respective tubes from opposite sides of the path of the film through the machine. In this way, it is possible, to feed two articles into successive tubes simultaneously, to increase the speed of packaging. The tube may be sealed at one end between the two transverse seals and this end seal may be formed before or after the opening out action, and the tube may also be sealed across that end through which the article enters after the article has arrived in place to completely envelope the article particularly if the film is to be heat shrunk on to the article. Whilst it would be possible to leave a series of packages joined together, it will, in most instances, be necessary to sever the film at each transverse seal to separate the packages from each other.

According to another preferred feature of the invention, apparatus for carrying out the method of forming a package comprises support means for a supply of two layers of plastics film, means for traversing the two layers of film, one superimposed upon the other, a sealing arrangement for sealing the two layers of film together on transverse lines at positions spaced in the direction of travel of the film, and opening means for opening out the flat envelope of film formed between two adjacent seals.

Preferably the apparatus includes a tube opening device, and a mechanism for controlling the tube opening device so that it is inserted between the two layers of film at a position on the input side of the sealing arrangement. The apparatus may also include producing relative transverse displacement between the opened out tube and an article to be wrapped, to introduce the article into the tube. The apparatus may also include a product conveyor means adapted to feed an article to be wrapped in the same sense as the film is fed.

Other preferred features of the invention will appear from the following description of a specific embodiment and various possible alternatives.

SPECIFIC EMBODIMENT A machine for producing packs, which is constructed and adapted to operate in accordance with the invention and its method of operation will now be described by way of example only with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view showing the general layout of the machine,

FIG. 2 is a diagrammatic elevation of a basic conveyor arrangement,

FIG. 3 is a diagrammatic plan view of the machine, showing packages being formed on the machine,

FIG. 4 is a perspective view of a film feed conveyer,

FIG. 5 is a detailed end view partly in section, and to a larger scale showing part of the film feed conveyor,

FIG. 6 is a plan view of the film feed conveyor showing the formation of bags thereon,

FIG. 7 is a perspective view of a sealer head operating mechanism,

FIG. 8 is a scale of part of the sealer head operating mechanism,

FIG. 9 is a perspective view of a carriage, part of which is also shown in FIG. 7,

FIG. 10 is a side view to a larger scale of a flicking mechanism shown in FIG. 9,

FIG. 1 1 is a detail perspective view of part of an indicator,

FIG. 12 is a front view partly in section of a sealer head,

FIG. 13 is a section on the line XIIIXIII in FIG. 12 showing the sealer head in detail,

FIG. 14 is a section substantially on the line XIV-XIV of FIG. 7 showing another part of the sealer head operating mechanism,

FIG. 15 is an end view of a product carrier shown in a retracted position,

FIG. 16 is a view looking in the direction of arrow XVI in FIG. 15,

FIG. 17 is a section on the line XVLL-XVLL in FIG. 15,

FIG. 18 is a section on the line XVIIIXVIII in FIG. 15,

FIG. 19 is a view similar to FIG. 15, but showing the carrier partially projected,

FIG. 20 is a view similar to FIG. 15, but showing the carrier fully projected and a finger mechanism activated,

FIG. 21 is a detail plan view of one end of the product carrier shown in FIG. 15,

FIG. 22 is a view looking in the direction of arrow XXII in FIG. 20, showing the pack opening mechanism in an operative position,

FIG. 23 is a detail view of a finger operating mechanism,

FIG. 24 is a diagrammatic plan view of a product feed framework,

FIG. 25 is a view similar to FIG. 17, but showing a pusher mechanism,

FIG. 26 is a plan view of the mechanism shown in FIG. 25,

FIG. 27 is a plan view of a pusher cam arrangement,

FIG. 28 is a perspective view showing the position after formation of a film tube with a finger opening mechanism in the closed position,

FIG. 29 is a perspective view showing the position of a tube after operation of the finger opening mechanism, and

FIG. 30 is a perspective view showing an alternative form of tube opening mechanism.

GENERAL LAYOUT OF MACHINE The purpose of the machine is to wrap articles of regular prismatic shape, and in this particular instance, the machine is intended to wrap rolls of wallpaper, which present a problem in that they are long relatively narrow articles. The rolls must be completely enveloped in heat shrinkable plastics film such as polyvinylchloride, ready for passing through a shrinking zone in which heat is applied to tighten the film on the'paper roll.

The machine is a processing machine having a series of stages at which a sequence of pack-forming steps is carried out. In this particular machine the stages are arranged along a horizontal path through the machine (the path being indicated by the line 10,10 in FIG. 2) but it is to be understood that this is a matter of convenience, and the machine could be arranged with a nonhorizontal path.

At the input end of the machine (shown at the left hand end in FIGS. 1 to 3) there is a film feed arrangement generally designated 12. The film feed will be hereinafter described in detail, but, it will be mentioned that there are vertically spaced mountings for reels l4 and 16 of the heat shrinkable plastics film, one above and one below the horizontal path 10..

The machine is adapted to bring the two films together and to produce a series of separate packages therefrom, as will be described, but it is necessary to mention at this stage, that the film travels successively over three conveyors; namely a film feed conveyor 18, a wrapper conveyor 20 and a shrink tunnel conveyor 22. The latter passes through a shrink tunnel 24 at the output end of the machine, this tunnel being a known apparatus in which heat is applied to the envelope of film to shrink that film into tight engagement with the article being wrapped.

The general path of the film through the machine as seen in plan is indicated by the chain dotted line 26,30,

32 and 34 in FIG. 3. From the film reelsl4 and 16, the

film passes in the path 26 at right angles to the general longitudinal path through the machine; then is turned through then it travels along the path 30 which is parallel with the general longitudinal path, and it leaves the machine along the path 34 which is parallel with the general path. It is to be observed however, that the paths 30 and 34 are offset from each other, and there is a short inclined path 32 between them, which is an important feature of the invention.

In front of the three conveyors 18, and 22, there is a product conveyor 36, and it will be seen that parts of this conveyor are alongside parts of all three film conveyors. The product conveyor 36 includes a series of carriers 38, which will be described in some detail hereinafter. It is to be noted however, that the carriers 38 do not travel in a rectilinear path as seen in plan (FIG. 3) but in a path designated 40, 42, 44, 46, 48 and 50. During the part of the carrier cycle indicated by the line 40, a carrier travels with a compound movement in the general longitudinal direction and also rearwardly towards the path of the film. Along the path 42, the carrier 38 travels parallel with the film, and then it travels in a compound stepped movement, indicated by the lines 44, 46 and 48 forwardly, away from the path of the film, and then along the path 50 parallel with the general longitudinal direction. From the path 50, the carriers 38 return along the bottom run of the conveyor 36. The wrapping function is performed by interaction of the articles carried by the product conveyor 36 and the film as it travels along the conveyors 18, 20 and 22.

To the rear of the film feed conveyor 18, there is a housing 54 for the main driving mechanism (not shown) of the machine, this driving mechanism including an electric motor and suitable gearing. A control panel 55 is also provided, this being connected to the housing 54 by a trunk 57.

FILM FEED The film feed 12 is a known type and therefore need not be described in great detail. It is designed to store the two reels of film 14 and 16 alongside the machine (see particularly FIG. 1) so as to keep the overall length of the machine as short as possible. The axes of the reels are therefore parallel with the general direction of travel through the machine. The reels are supported on a stationary frame 52 which may form part of the general fixed structure of the machine, (as illustrated in FIG. 1) or it may be a free-standing unit which is simply placed in close juxtaposition with the housing 54 for the main driving mechanism.

An arm 56 extends forwardly from the housing 54, and at its extremity, it provides a support for one end of a cylindrical rod 58, the other end of which is supported in a lug 60 on the frame 52. The rod 58 is inclined at 45 to the axes of the film reels and to the general path of the film through the machine as seen in plan view. This rod provides a means for changing the direction of travel of the film through an angle of 90. The rod 58 is in a position to receive the film from the upper reel 14, and there is a similar rod 62 for the film from the lower reel 16, the rod 62 being supported at one end in a lug 64 and at its other end by an arm (not visible in FIG. 1) which is similar to the arm 56.

Two sets of film tensioning rollers are provided in the film feed assembly 12, one set for each film reel. The upper set comprises three parallel rollers 66, 68 and 70 each extending across the path of the film from the reel 14 to the rod 58, these rollers being journalled so that they are able to rotate about their respective longitudinal axes. The top set also includes two rollers 72 and 74 mounted parallel with the rollers 66, 68 and 70 and interdigitated therewith. Each roller 72 and 74 is free to rotate about its own longitudinal axes, and in addition, its axle is free to rise and fall in corresponding vertical slots 76 (two of which can be seen in FIG. 1) formed in the frame 52 and in the housing 54.

The film 80 from the top reel 14 passes in a sinuous path over the roller 66, under roller 72 and over roller 68, under roller 74 and over roller 70 to the rod 58. In turning under the rod 58, the film 80 is then passed in a direction indicated by the line 30 in FIG. 3 longitudinally of the machine.

The weight of the rollers 72 and 74 is carried by the film 80, and consequently these rollers tension the film. Also the sinuous extension of the film provides a film reservoir which has already been pulled off the reel 14. If the machine requires film more rapidly than it can conveniently be withdrawn from the reel, then the extra film is drawn from the reservoir, the rollers 72 and 74 rising to shorten the path through the reservoir. Conversely, if the film requirement of the machine is less than the rate of feed from the reel, then the rollers 72 and 74 are lowered and the length of the film reservoir is increased.

The lower set of tensioning rollers comprises three stationary rollers 82, 84 and 86 and two vertically movable rollers 88 and 90, in an arrangement which duplicates that of the upper tensioning rollers. The film 92 from the lower reel 16 passes through the reservoir provided by the rollers, 82, 88, 84, and 86 and then under an extra guide roller 93 before turning under the turning rod 62 in similar fashion to the upper film 80.

The film feed is completed by upper and lower pairs of nip rollers 94 and 96 which are vertically spaced from each other, the rollers of each pair being spring loaded towards each other, and a pair of guide rollers 98 and 100 which are spaced apart a short distance. After leaving the turning rod 58, the film 80 passes through the nip rollers 94 and then under the guide roller 98. The film 92 on the other hand, after leaving its turning rod 62 passes through the nip rollers 96 and over the guide roller 100.

At the guide rollers 98 and 100, the two films 80 and 92 form a mouth, but beyond these rollers the film layers are brought together in a face-to-face relationship by a mechanism to be described, so that they are ready to be formed into an envelope. The film feed provides a means of supplying the film from the two reels 14 and 16 to the rollers 98 and 100. It is, of course, necessary to ensure that the two films are correctly aligned with each other transversely of the machine, and generally the films will be of equal width (as illustrated) so that their longitudinal edges have to be brought into overlying relationship. For this purpose an axial adjustment of the reels 14 and 16 is provided, so that one reel can be moved in an axial direction relatively to the other reel. This is a known method of aligning the two film feeds.

An important feature of the machine is that the top roller 98 does not extend as far forwardly as the bottom roller 100.

It is to be understood that the use of a film feed which has its reels parallel to the general path of the film through the machine is not essential. It would be possible to provide a feed mechanism having a pair of reels with their axis transversely disposed in the machine, so 

1. A method of forming a package containing an article comprising the steps of feeding a web comprising two layers of wrapping film in close juxtaposition along aligned paths of travel in the same direction, inserting an expansible tube opening device between said two layers of film, causing a sealed relationship between said two layers of film in separate transversely extending areas located at opposite sides of the inserted device and spaced apart relative to said direction of travel to form a compartment for said inserted device, severing the web at said areas to separate said compartment from said web, then expanding said inserted tube opening device for opening out said compartment to form a tube having at least one open end and frictionally grip the interior of said tube, and supporting and conveying said severed tube in said direction of travel by said tube opening device while inserting an article to be packaged into the open end of said tube.
 2. A method of forming a package according to claim 1, wherein said two layers of film are made of thermoplastic material, and heat is applied at said transversely extending areas to sever both layers of film on a transverse line of cut and to form seals between said two layers of film one in advance of and the other to the rear of said line of cut.
 3. A method of forming a package according to claim 2, wherein said two layers of film are superimposed one upon the other as said layers are being fed and sealed, and whereby when said seals are formed, said two layers are stretched lengthwise between said seals to form a substantially flat envelope.
 4. The method defined in claim 1 wherein said tubes are continually formed and disposed in separate succession longitudinally forwardly of the leading end of the juxtaposed layers and articles are advanced in synchronous succession toward a loading station wherein each article is inserted iNto a tube by relative movement between the tube and article.
 5. The method defined in claim 4, including the step of positively separably displacing each formed tube at said leading end rapidly forwardly prior to insertion of the article.
 6. The method defined in claim 1 wherein both the article and the tube are moved endwise towards each other during insertion of the article.
 7. The method defined in claim 1, including the step of withdrawing said inserted device following at least partial insertion of said article into said tube.
 8. The method of forming a package according to claim 1, wherein said article and tube are advanced in side-by-side paths and said article and tube are automatically moved laterally relatively to each to contain the article within the tube during said advance.
 9. A method of forming a package as claimed in claim 8, which includes the further step of subjecting the tube containing the article to a heat shrinking operation.
 10. Apparatus for forming a package containing an article comprising means for feeding a web comprising two layers of wrapping film in close juxtaposition along aligned paths of travel in the same direction, tube opening means mounted for movement in said direction of travel and actuatable between a first non-expanded condition wherein it may be inserted between said film layers and a second expanded condition, means for inserting said tube opening means while in non-expanded condition between said two layers of film, means for causing a sealed relationship between said two layers of film at transversely extending separate areas located at opposite sides of the inserted tube opening means and spaced apart relative to said direction of travel to form a compartment for said inserted device, means for severing the web at said areas to separate individual compartments from the web, means for actuating said inserted tube opening means to expanded condition for opening out the associated severed compartment to form a separated tube having at least one open end, said opening means including means for frictionally gripping the interior of said tube to support and convey said tube in said direction of travel, and means for introducing an article to be wrapped into the open end of said tube.
 11. Apparatus as defined in claim 10 wherein said film layers are continuous webs of material, means is provided for forming and separating said tubes in succession automatically at the leading end of the web of juxtaposed films, and means is provided for advancing articles in synchronous succession with said tubes toward a loading station wherein means is provided for inserting each article into a tube by relative displacement therebetween.
 12. Apparatus as claimed in claim 11, in which the means for producing relative transverse displacement between the tube and an article to be wrapped, to introduce the article into the tube, comprises means for displacing the article and the tube toward each other.
 13. Apparatus as claimed in claim 10, which also includes a product conveyor means adapted to feed an article to be wrapped in the same sense as the web is fed.
 14. Apparatus as claimed in claim 13, in which the product feed conveyor is provided with a plurality of product carriers each of which is mounted for lateral movement towards and away from the path of movement of the web.
 15. Apparatus as claimed in claim 13, in which the tube opening means is carried by the product conveyor means.
 16. Apparatus as claimed in claim 15, in which the tube opening means is connected to be operated by the movement of that device produced by the product conveyor means.
 17. Apparatus as claimed in claim 16, including stationary cam means and in which the tube opening means is provided with an operating mechanism including a part engageable with said stationary cam means during feeding of the tube opening means on the product conveyor.
 18. Apparatus as claimed in claim 17, in which the tube opening means includes tube eNgaging members that initially lie in a collapsed condition in a substantially flat plane between the paths of the two film layers, the said tube engaging members being articulated so that, when activated, they move from the collapsed condition to an erect condition.
 19. Apparatus as claimed in claim 18, in which the tube engaging members are mounted to turn about respective pivots from the collapsed to the erect condition, the operating mechanism being adapted to convert a rectilinear motion of a cam engaging part into turning motion of the tube engaging members.
 20. Apparatus as claimed in claim 14, in which a pusher is mounted to move laterally on each carrier to push an article to be wrapped from the carrier into a film tube, and activating mechanism for the pusher is provided which operates the pusher in response to travel of the carrier on the product conveyor.
 21. Apparatus as claimed in claim 10, in which said means for causing said sealed relationship includes a sealer head carried by a mechanism constructed and arranged to reciprocate the head parallel with the path of feed of the film, and to move the sealer head towards and away from the film to effect the sealing operations in timed relationship to the speed of travel of the film.
 22. Apparatus as claimed in claim 21, in which the sealer head mechanism includes an oscillating motion transmitter of variable stroke length, but with a period directly related to the speed of film feed.
 23. Apparatus as claimed in claim 22, in which the motion transmitter comprises a lever which turns on a fulcrum which is adjustable to vary the effective length of at least one arm of the lever.
 24. Apparatus as claimed in claim 21, including a film feed conveyor to carry the film through the zone of operation of the sealer head and the sealer head being supported by a reciprocable carriage having rollers adapted to engage on the film and to hold the film on to the film feed conveyor.
 25. Apparatus as claimed in claim 24, in which means is provided whereby at least one roller of the sealer head is given a sudden rotation at the end of the movement of the carriage in the same direction as the film, for the purpose of pulling a formed tube of film away from the following bulk of film.
 26. Apparatus as claimed in claim 21, including a cam driven in synchronism with the film feed and operably connected to periodically depress the sealer head against a resilient loading to periodically move the head into engagement with the film.
 27. Apparatus as claimed in claim 10, in which there is a heat shrink tunnel and conveyor means for carrying the wrapped article into the tunnel.
 28. Apparatus as defined in claim 10 wherein said means for causing said sealed relationship between the films comprises a support over which said films are moved in superposed relation, a transversely extending heat sealing and film severing head mounted above said support for reciprocation in the path of film movement, and means for cyclically moving said head down onto the moving film on said support, moving said head a predetermined distance along said support in contact with the film, separating the head from said film and returning the head back along the support to initial position.
 29. Apparatus as defined in claim 28, wherein said head is mounted on a reciprocable carriage and cam means is provided for reciprocating said carriage along said support, and resilient means is provided between said head and carriage whereby said head is biased to separate from said film, and cam means driven is synchronism with the cam means for reciprocating the carriage is operably connected to said head to displace the head into engagement with the film during displacement of said carriage in said film feed direction.
 30. Apparatus as defined in claim 28, wherein said support is the upper flight of an endless conveyor driven in the direction of film feed, said head is supported on a reciprocable carriage having rollers in contact with the film On the support, and means is provided for synchronizing the speed of said conveyor flight with the speed of said carriage in the film feed direction.
 31. Apparatus as defined in claim 30, wherein means is provided for positively rotating said rollers during return reciprocation of said carriage whereby to substantially eliminate slipping between the film and rollers.
 32. Apparatus as defined in claim 30, wherein said support conveyor comprises a resiliently backed endless belt.
 33. Apparatus as defined in claim 10 wherein said tube gripping means is disposed to grip said tube adjacent the open end of the tube and support means is provided underlying the opposite end of the separated tube as it is conveyed by said tube opening means. 